Been using the BBPress plugin on a clients site and even knowing it is a Release Candidate atm it's pretty damn good already. I have not noticed any problems which would affect it being used on a live site.

Only problem I have had is adjusting the WordPress theme I was using to work with it properly, other then that a few theme tweaks and BBPress plugin tweaks fixed those issues.

Looking forward to the final version. I will be integrating it into PWPH.